Vinyl chloride polymers plasticized with adducts of fumarate esters and alkenyl-substituted aromatic compounds



j in the addition reaction.

United States Patent Claims. (Cl. 260-315) This invention relates tohigh molecular weight adducts and more particularly provides new vinylaromatic compounds having a plurality of carboxylate radicals, theprocess of producing the same, and vinyl chloride resins plasticizedwith the new compounds.

An object of the invention is the provision of new and usefulpolycarboxylates. Another object of the invention is the preparation ofviscous polycarboxylates from certain vinyl-substituted aromatichydrocarbons. Still another object of the invention is to provide forthe coatings, synthetic resins and plastics, plasticizer, rubber andtextile industries a new class of stable, viscous materials having aplurality of carboxylate radicals.

These and other objects of the invention hereinafter disclosed areprovided by the following invention wherein there are prepared viscousadducts of (1) an ester selected from the class consisting of alkyl andalkoxyalkyl fumarates having from 1 to 8 carbon atoms in the alkylradical and from 3 to 8 carbon atoms in the alkoxyalkyl radical and (2)vinyl-substituted aromatic hydrocarbons selected from the classconsisting of styrene, ar-vinyltoluene, a-methylstyrene and dimerica-methylstyrene, i.e., 2,4-diphenyl-4-methyl-l(or 2-) pentene. Thear-vinyltoluene may be a mixture of 2-, 3- or 4-vinyltoluene in anyproportion or one of said isomers alone, ar indicating substitution inthe aromatic nucleus.

Fumara-tes suitable for the present purpose are the simple alkyldiesters of fumaric acid, e.g., methyl, ethyl, isopropyl, n-propyl,n-butyl, tert-butyl, isoamyl, n-hexyl, n-heptyl Z-ethyl-hexyl andn-octyl fumarate, the mixed alkyl diesters, e.g., ethyl methylfumara-te, isopropyl n-octyl fumarate, n-amyl tert-butyl fumarate, etc.,the simple alkoxyalkyl fumarates such as bis(2'methoxyethyl), bis-(3-ethoxy-npropyl), and -bis(4-butoxy-butyl) fum arates; the mixedalkoxy-alkyl fumarates such as 3-propoxypropyl 2-ethoxyethyl fumarate ormethoxymethyl Z-amyloxyethyl fumarate and fumarates derived from both afatty alcohol and a glycol mono-ether such as ethyl 2-ethoxy- 'ethylfumarate or n'amyl 3-propoxy-2-propyl fumarate.

While I do not understand the mechanism by which addition of thefumarate to the present vinyl aromatic compounds occurs, it probablytakes place at the carbon atom or atoms which are ato the carbon atomsattached to the olefinic double bond of the vinyl aromatic compound. Theolefinic double bonds of the hydrocarbon remain intact, whereas those ofthe fumarate are saturated Depending upon the reaction conditions andthe nature of the fumarate and vinyl aro-,

matic hydrocarbon, from 1 to 3 moles of fumarate add to saidhydrocarbon. Hence the present compounds have from 2 to 6 carboxylategroups, two groups being present provided adducts is:

in which R is selected from the class consisting of the sty- 3,048,558Patented Aug. 7, 1962 ice rene, a-methylstyrene and dimerica-methylstyrene residues, Y and Y' are alkyl radicals of from 1 to 8carbon atoms and n is an integer of 1 to 3.

Reaction of one of the present vinyl aromatic hydrocarbons with thealkyl fumarate to form viscous adducts takes place readily by heating amixture of the fumarate and said hydrocarbon in the presence or absenceof an inert diluent or solvent at ordinary or super-atmosphericpressures. When operating at atmospheric pressure, temperatures offrom,'say, C. to 300 C., and preferably of from C. to 225 C., are used.The number of carboalkoxy groups introduced into the vinyl hydrocarbondepends upon the nature of said product, upon the nature of theindividual fumarate used, and upon the reaction conditons employed.Generally, operation within the higher temperature ranges, i.e., attemperatures of above, say, 210 C. and below the decomposition point ofany of the reactants, leads to introduction of more carboalkoxy groupsthan does operation at the lower temperatures. The number of carboalkoxygroups introduced also depends upon the individual fumarate employed.Usually alkyl fumarates having 4 or 5 carbon atoms in the alkyl radicalare more reactive than the higher alkyl fumarates. In view of the effectof the reaction conditions and nature of the fumarates upon the extentof introduction of carboalkoxy groups, it is recommended that for eachinitial run there be experimentally determined the operating conditionswhich should be observed for obtaining the desired degree ofintroduction of such groups.

The quantity of fumarate introduced into the vinyl aromatic hydrocarbonwill also depend upon its availability in the reaction mixture.Obviously, for the formation of adducts in which at least one mole ofthe fumarate has added to one mole of the unsaturated hydrocarbon, theequivalent amount of fumarate must be present in the reaction mixture.

Since the presently useful fumarates are miscible with the hydrocarbonreactant under the reaction conditions employed, no extraneous solventor diluent need be ernployed. However, in some instances, it may beadvantageous to work with a solution of the hydrocarbon in an inert,extraneous diluent or solvent, e.g., a liquid hydrocarbon or a liquidderivative thereof, such as a high-boiling aliphatic hydrocarbon, e.g.,kerosene. When operating at atmospheric pressure such diluent isgenerally removed before reaction of said vinyl hydrocarbon with thefumarate occurs, due to the high temperatures used. For successfulreaction, the diluent may or may not be present.

The present vinyl aromatic hydrocarbon-alkyl furnarate adducts arestable, highboiling viscous liquids which are advantageously employedfor a variety of industrial pur poses, for example, as textile and papertreating agents, as lubricant additives, and as synthetic resins for usein varnishes, asphaltic compositions, etc. They are particularlyvaluable as plasticizers for vinyl chloride polymers. The presentadducts are completely compatible with such polymers and show noexudation of plasticizer even at plasticizer contents of up to 50percent. Although the quantity of plasticizcr will depend upon theparticular polymer to be plasticized and upon its molecular weight, itis generally found that compositions having from 5 percent to 50 percentby weight of the present plasticizer will, in most cases, besatisfactory for general utility. The good flexibility of theplasticized compositions increases with increasing plasticizerconcentration.

The invention is further illustrated but not limited by the followingexamples:

Example 1 A mixture consisting of 118 g. (1 mole) of a-methylstyrene,456 g. (2 moles) of butvl fumarate and about 1.0 g. ofdi-tert-butylcatechol (as polymerization inhibitor) was heated at 220 C.for 8 hours in a rocking autoclave. The refractive index of the reactionmixture rose from an initial n of 1.4638 to 1.4822. Distillation of theresulting reaction mixture to remove material boiling below 205 C./1.8mm. gave as residue 419 g. of the viscous light yellowa-methylstyrcne-dibutyl fumarate adduct, n 1.4910 and having an iodinenumber of 8.56 and 8.63 in two diiferent determinations. Analysis ofsaid residue showed it to be a product in which one mole ofwmethylstyrene is combined with two moles of butyl fumarate, saidresidue having the following analysis:

Example 2 A mixture consisting of 157 g. (1.5 moles) of styrene, 684 g.(3 moles) of dibutyl fumarate, and a polymerization inhibitor consistingof 2.0 g. of di-tert-butylcatechol and 1.0 g. of sulfur was heated in arocking autoclave for 8 hours at 220 C. During the heating period therefractive index of the reaction mixture rose from 11 1.4638 to 1.4832.Removal of material boil ing below a pot temperature of 230 C./2 mm.gave as residue 650 g. of a yellow, viscous adduct, n 1.4943 whichanalyzed 70.13% C and 8.72% H. Since the calculated values for a 1:1styrene-butyl fumarate adduct are 72.3% C and 8.45% H and those of a 1:2styrenebutyl fumarate adduct are 68.7% C and 8.57% H, said residuerepresents a substantially equimolar mixture of 1:1 and 1:2styrene-butyl fumarate adducts.

Example 3 This example describes the preparation of an addition productfrom butyl fumarate and dimeric a-methylstyrene. The dimerica-methylstyrene was a commercially available product which was a mixturereputed to consist of about 43% 2,4-diphenyl-4-methylpentene-1, 49% of2,4-diphenyl-4-methylpentene-2 and about 8% of indene-type hydrocarbons.A mixture consisting of 118 g. (0.5 mole) of the dimeric a-methylstyrenen 1.5677 and 456 g. (2 moles) of butyl fumarate was brought to atemperature of 220 C. in about 30 minutes and heating at a temperatureof from 218-235 C. was continued for about 5.5 hours. During the heatingperiod 1.0 g. of di-tert-butylcatechol (as polymerization inhibitor) wasadded to the reaction mixture in several portions. Distillation of theresulting reaction mixture to remove material boiling below 205 C./ 1.5mm. gave as residue 318 g. of an adduct of butyl fumarate and thedimeric u-methylstyrene, 11 1.4825. It was found to have asaponification equivalent of 161.2 (average of 2 values), which valuecorresponds to an adduct in which one mole of the dimerica-methylstyrene is combined with an average of 2.5 moles of butylfumarate.

Example 4 A mixture consisting of 118 g. (1 mole) of a commerciallyavailable ar-vinyltoluene, 11 1.5386, 520 g. (2 moles) of Z-ethoxyethylfumarate, and as inhibitor 2.0 g. of di-tert-butylcatechol and 1.0 g. ofsulfur was heated in an autoclave at 220 C. for 8 hours. During thistime the refractive index of the reaction mixture rose from 1.4685 to1.4850. The reaction product was transferred to a distilling vessel, theautoclave was washed out with acetone, and the combined product andwashings were distilled to remove 169 g. of the unreacted 1 fumarate n1.4512. There was thus obtained as residue 462 g. of the substantiallypure 1:1 vinyltoluene-Z-ethoxy- 4 ethyl fumarate adduct, n 1.5001,having a saponification value of 196 as against 189, the theoreticalvalue.

Example 5 Sixty parts by weight of polyvinyl chloride and 40 parts byweight of the tx-methylstyrene-butyl fumarate adduct of Example 1 weremixed on a milling roll to a homogeneous blend. During the milling therewas observed substantially no fuming or discoloration. A molded sheet ofthe mixture was clear and transparent and substantially colorless.Testing of the molded sheet for low temperature flexibility by theClash-Berg method gave a value of 0.0 C. Testing of the volatilitycharacteristics of the molded resin by a modified carbon absorptionmethod of the Society of Chemical Industry gave a value of 1.7%. Whensubjected to heat at a temperature of 325 F. for a period of 30 minutesthe clarity and color of the molded product was substantially unchanged.Testing of the water resistance of the plasticized material by immersingin water for 24 hours showed a solidsloss of only 0.01 percent and an0.34 percent Water absorption value.

When the dimeric a-methylstyrene-butyl fumarate adduct of Example 3 wastested as a plasticizer for polyvinyl chloride employing vtheproportions and procedure used above for the adduct of Example 1, therewas obtained a clear, compatible plasticized material having lowtemperature flexibility value of minus 4.9 C., a volatility value of2.5%, a solids-loss of 0.18% and a water absorption value of 0.58%. Thekerosene resistance of a molded test specimen of polyvinyl chlorideplasticized with 40 percent by weight of the adducts of Examples 1 and 3was determined as follows:

A 2" diameter 40 mil. disc was suspended in a 50 C. oven for a 3-hourconditioning period to eliminate water, then cooled and weighed. Theso-conditioned sample was then immersed in 400 ml. of kerosene for aperiod of 24 hours, at 27 C. The sample was then removed from kerosene,blotted dry and suspended in a force-draft C. oven for 4 hours. Thesample was then cooled and weighed. The percent loss in weight wasreported as the kerosene extraction value. There was thus obtained akerosene extraction value of 0.1% for the a-methylstyrene adduct ofExample 1 and a value of 0.5% for the dimeric a-rnethylstyrene adduct ofExample 3.

Instead of the butyl fumarate adducts, adducts of styrene,wmethylstyrene, dimeric u-methylstyrene or vinyltoluene and other alkylfumarates, e.g., methyl or 2- ethylhexyl fumarate or al-koxyalkylfumarates such as 3- ethoxypropyl or 4-butoxybutyl also give goodresults as polyvinyl chloride plasticizers. Thus by employing 40 partsby weight of the adduct of methyl or ethyl fumarate and 2-, 3- or4-vinyltoluene or the adduct of 2-butoxyethyl or 2-methoxypropylfumarate and 60 parts by Weight of a vinyl chloride-vinyl acetatecopolymer known to the trade as Vinylite there are obtained clear,colorless compositions of very good flexibility and stability.

While the above example shows only compositions in which the ratio ofplasticizer to polymer content is 40:60, this ratio being employed inorder to get comparable values, the content of adduct to polyvinylchloride may be widely varied, depending upon the properties desired inthe final product. [For many purposes a plasticizer content of, say,from only 10 percent to 20 percent is preferred. The present adducts arecompatible with polyvinyl chloride over wide ranges of concentrations,up to 50 percent of adduct based on the total weight of the plasticizedcomposition yielding desirable products.

Although the invention has been described particularly with reference tothe use of the present adducts as plasticizers for polyvinyl chloride,they are advantageously employed also as plasticizers for copolymers ofvinyl chloride, for example, the copolymers of vinyl chloride with vinylacetate, vinylidene chloride, etc. Preferably,

such copolymers have a high vinyl chloride content, i.e., a vinylchloride content of at least 70 percent by weight of vinyl chloride andup to 30 percent by weight of the copolymerizable monomer.

The plasticized polyvinyl halide compositions of the present inventionhave good thermal stability; however, for many purposes, it may beadvantageous to use known stabilizers in the plasticized compositions.Inasmuch as the present adducts are substantially unreactive with thecommercially available heat and light stabilizers which are commonlyemployed with polyvinyl chloride or copolymers thereof, the presence ofsuch materials in the plasticized resins does not impair the valuableproperties or" the present esters. The present adducts are of generalutility in softening vinyl chloride polymers. They may be used as theonly plasticizing component in a compounded vinyl chloride polymer orthey may be used in conjunction with other plasticizers.

This application is a division of my copending application, Serial No.579,452, filed April 20, 1956, now US. Patent No. 2,913,482, grantedNov. 17, 1959.

What I claim is:

1. A resinous composition comprising polyvinyl chloride plasticized withan adduct of the formula in which R is selected from the classconsisting of the styrene, ar-vinyltoluene, a-methylstyrene and dimericu-methylstyrene residues, Y and Y are selected from the class consistingof alkyl radicals of from 1 to 8 carbon atoms and alkoxyalkyl radicalsof from 3 to 8 carbon atoms, and n is an integer of 1 to 3, said adductbeing present in the resinous composition in a quantity of from 5% to50% by weight.

2. A resinous composition comprising a copolymer of at least 70% byweight of vinyl chloride and up to 30% by weight of an unsaturatedmonomer selected from the class consisting of vinyl acetate andvinylidene chloride, said copolymer being plasticized with an adduct ofthe formula R- CHCOOY [(BHgOOOYZL in which R is selected from the classconsisting of the styrene, ar-vinyltoluene, m-methylstyrene and dimerica-methylstyrene residues, Y and Y are selected from the class consistingof alkyl radicals of from 1 to 8 carbon atoms and alkoxyalkyl radicalsof from 3 to 8 carbon atoms, and n is an integer of 1 to 3, said adductbeing 6 present in the resinous composition in a quantity of from 5% to50% by weight.

3. The resinous composition defined in claim 1 further characterized inthat R is the styrene residue and Y and Y are alkyl radicals of from 1to 8 carbon atoms.

4. The resinous composition defined in claim 1 further characterized inthat R is the u-methylstyrene residue and Y and Y are alkyl radicals offrom 1 to 8 carbon atoms.

5. The resinous composition defined in claim 1 further characterized inthat R is the dimeric a.-methylstyrene residue and Y and Y are alkylradicals of from 1 to 8 carbon atoms.

6. The resinous com-position defined in claim 1 further characterized inthat R is the styrene residue and Y and Y are butyl radicals.

7. The resinous composition defined in claim 1 further characterized inthat R is the a-methylstyrene residue and Y and Y are butyl radicals.

8. The resinous composition defined in claim 1 further characterized inthat R is the dimeric wmethylstyrene residue and Y and Y are butylradicals.

9. The resinous composition defined in claim 1 further characterized inthat R is the ar-vinyltoluene residue and Y and Y are 2-ethoxyethylradicals.

10. A resinous composition comprising a polymer selected from the classconsisting of polyvinyl chloride and copolymers of at least by weight ofvinyl chloride and up to 30% by weight of an unsaturated monomerselected from the class consisting of vinyl acetate and vinylidenechloride, said polymer being plasticized with an adduct of the formulain which R is selected from the class consisting of the styrene,ar-vinyltoluene, a-methylstyrene and dimeric a-methylstyrene residues, Yand Y are selected from the class consisting of alkyl radicals of from 1to 8 carbon atoms and alkoxyalkyl radicals of from 3 to 8 carbon atoms,and n is an integer of 1 to 3, said adduct being present in the resinouscomposition in a quantity of from 5% to 50% by weight.

References Cited in the file of this patent UNITED STATES PATENTS2,442,558 DAlelio June 1, 1948 2,667,504 Dazzi Jan. 26, 1954 2,897,230Dazzi July 28, 1959

10. A RESINOUS COMPOSITION COMPRISING A POLYMER SELECTED FROM THE CLASSCONSISTING OF POLYVINYL CHLORIDE AND COPOLYMERS OF AT LEAST 70% BYWEIGHT OF VINYL CHLORIDE AND UP TO 30% BY WEIGHT OF AN UNSATURATEDMONOMER SELECTED FROM THE CLASS CONSISTING OF VINYL ACETATE ANDVINYLIDENE CHLORIDE, SAID POLYMER BEING PLASTICIZED WITH AN ADDUCT OFTHE FORMULA